[MIM 613 834 ]

Prevalence : < 1.106.  De novo heterozygous mutation of the ACTA2 gene, at the level of Arg 179,  (10q23.31) producing the association of:

• congenital mydriasis (100 %) with iris hypoplasia  or aniridia, and tortuosity of the central retineal artery in some cases
• a patent ductus arteriosus (91 %) or an aortopulmonary window, sometimes associated with a cardiac malformation (aortic arch anomalies, ASD)
• systemic BP lower than in the normal population, due to lower vascular resistances
• pulmonary arterial hypertension
• aortic dilation and aneurysms (with sometimes inaugural type A or B dissection) (median age at 1st surgery : 14 years) (100 %) ; other arteries are also involved (54 %) : pulmonary, carotid, axillary, iliac…)
• a moyamoya-like cerebrovascular disease (see this term) (77 %) with ischemic infarction in childhood, risk of epilepsy
• upper airway hypotonia: obstructive sleep apneas, malacia, hyperreactivity
• intestinal malrotation intestinale (30 %) with hypoperistaltism
• a hypotonic bladder (47 %) with a risk of bladder lithiasis and hydronephrosis (30 %), sometimes Prune-Belly syndrome (see this term)

There is a high risk of early death  following an aortic dissection, a stroke or pulmonary complications.

Treatment: ACEI or inhibitors of the angiotensin II receptors

Anesthetic implications:

a)        preoperatively:

• cardiac and large vessels echography: malformation, aneurysms, pulmonary hypertension ? ; renal function
• check the baseline blood pressure to have a perioperative reference value
• interrupt antihypertensive drugs the day before the procedure

b)        intraoperatively:

• pre-existing mydriasis
• significant risk of systemic hypotension: coronary and cerebral circulations at risk of ischemia
• avoid hyper- and hypoventilation (major risk of regional cerebral hypoperfusion); NIRS monitoring
• avoid episods of systemic high blood pressure (intubation, pain)
• anticipate continuous administration of a vasopressor (norepinephrine, vasopressin)

c)        operatively:

• intensive care monitoring because of risk of cerebral ischemia

References :

-        Regalado ES, Mellor-Crummey L, De Backer J, Braverman AC Ades L et al.
Clinical history and management recommendations of the Smooth Muscle Dysfunction syndrome due to ACTA2 Arginine 179 alterations.
Genet Med 2018; 20: 1206-15.

-        Houska N, Schafer M, Chatfield KC, Bernard TJ, Ing RJ.
Anesthetic considerations for children with multisystem smooth muscle dysfunction syndrome and review of the literature.
J Cardiothor Vasc Anesth 2022, 2022, 36 : 3205-11

Update September 2022